The Brits have been blending beer for over three centuries. Porter, in fact, evolved from a beer cocktail called three threads, a mix of pale ale, brown ale and well-aged sour beer.

The black and tan -- properly, a blend of Guinness Draught and Bass (or a similar pale ale) -- dates from the 19th century. The half and half, a mixture of Guinness and lager, is a more recent innovation, as Guinness didn't begin tapping the lager market with its Harp brand until 1960.

I'm not sure who came up with the idea of the beer parfait, an ebony layer of stout resting almost magically atop a base of golden ale or lager. It's an eye-catching combo, bringing out the visual appeal of both beers, which would otherwise coalesce into a murky brown. (Or as Bass brand manager John Costello puts it, it's "a new way to engage the consumer.") But you don't need a master's degree in mixology, just a spoon and some patience, to concoct your own.

For maximum effect, Murray advises using a British 20-ounce pint glass with a bulge at the top instead of the American straight-sided pint. First, fill the glass three-quarters of the way to the rim with the golden beer. Because the glass is wider at the top, you'll wind up with roughly equal amounts of both components. Next, slowly dribble in the Guinness over the back of a spoon. "Try to get it to flow down the sides of the glass," Murray says. (Guinness provides its accounts with a special spoon with a kink in the stem that fits over the rim of the glass.)

Alternatively, you can use the Bass "brolly" (British slang for umbrella), a triangular device that attaches to the top of your pint and contains 12 tiny perforations to let the stout trickle down gently. (You can order one at http://www.bass.com.) It works, but you must pour slowly, because the creamy stout foam tends to gum up the holes.

Left undisturbed, the layers should remain distinct for up to a half-hour, Murray says. The tilting of the glass as you down the drink will cause the beers to mix more rapidly.

Layered beer drinks are an American innovation, Murray says. If you ask for one in Dublin, the publican might try to oblige you, but don't blame him if he falls short. The Smithwick's and Harp served in Ireland are lighter than the American versions and can't support a topping of Guinness.

The American beer scene permits many substitutions in the classic recipes. Most pale ales, American lagers or wheat beers can take the place of Harp or Bass. If you want a hoppier counterpoint to the coffeelike flavors of the stout, use Sierra Nevada Pale Ale, Anchor's Liberty Ale or Yuengling's Lord Chesterfield Ale.

No Guinness on hand? You can substitute Murphy's Stout, Beamish Stout or O'Hara's Celtic Stout (the latter a roastier, more aggressive version of the style from a microbrewery in Carlow, Ireland). Anheuser-Busch's draft-only Bare Knuckle Stout is similar to Guinness in taste and strength. Ask your bartender to top off the pale, citrusy Widmer Hefeweizen with some Bare Knuckle to make a lava lamp, so named because the stout tends to bob up and down like the globules in the lamp.

Be warned: Many American microbrewery stouts are much heavier than Guinness Draught, particularly if they're prefaced by the adjective "imperial." But you can sometimes reverse the order of the layers. Try topping off a Shakespeare Stout from Rogue Ales in Newport, Ore., with that brewery's Kells Irish Lager. (An O'Shakespeare?)

As you become more adept, try your hand at a "tiger tail," with a bottom layer of imperial stout propping up layers of pale ale and Guinness Draught.

As with any artistic endeavor, layering beer takes practice. But take comfort in the knowledge that you can always drink your failures.

Greg Kitsock's Beer column appears every other week. He can be reached at food@washpost.com.